“All he wanted to do was live for Friday and Saturday night, going out drinking.

“I was the same. I was only 19 when I met him.

“I’d gone with him to Jamie’s fights over the years. He never used to be ringside, he was always in the stands drinking with his mates.”

A key figure in the story is, of course, McDonnell’s twin brother Jamie, the WBA bantamweight champion.

His boxing career began long before and had been rejuvenated by the time his brother entered the sport. Jamie’s European title win was the tipping point for McDonnell jumping into boxing with two feet.

Jamie McDonnell: “I can’t remember a massive amount about that night because by that point, we’d done plenty of boozing.

“But he’d been saying for ages that he was going to come to the gym. I’d always be ‘Aye, all right kid.

“So we’ll have just laughed it off again when he said that in France.

“But to be fair to him, he stuck to his word.”

Stefy Bull has been McDonnell’s manager since he decided to give professional boxing a go.

In the early days, he was also his co-trainer, alongside Dave Hulley who would eventually train both Jamie and Gavin in Lindholme.

But he has been McDonnell’s friend long before he ever laced up a pair of gloves.

Stefy Bull: “The story really goes back before that night in France that everyone talks about.

“It goes back to a time when Gav was on the weights and someone who lived for the weekend.

“He’d knock off early on a Friday from plastering and might not make it home until Sunday.

“He had a reputation as the village idiot, a bit of a nuisance in the pub.

“So you can imagine what everyone thought when he stood up at that table in France, as a 25-year-old, at 11 and a half stone, drunk and said what he said.

“We just laughed and told him to sit down.”

Friends and family may have laughed but what they did not know was McDonnell was deadly serious.

A switch was flicked in his mind that he himself still struggles to explain.

And his determination has never diminished in the seven years since.

SM: “From that day in France, he borrowed some of Jamie’s gear and went to the gym.

“And he’s never stopped since.”

SB: “The week after, he turned up in the gym. All of kit was borrowed from Jamie.

“We started work and it’s no exaggeration to say he didn’t know his right hand from his left. It looked a hopeless cause.

“I wish I’d got some footage from those early days because people wouldn’t believe it.

“But he just wanted to work and learn. He put everything into it.

“We’d sort of got used to Jamie disappearing after fights and it being a bit of a battle to get him in the gym but Gav was the opposite.

“We found out about 18 months after his debut that he’d been going out running after he’d been in the gym. He’d work plastering all day, come to the gym for 7pm and then go running afterward.

“You couldn’t stop him. That’s how much he wanted it.”

JM: “He didn’t really know what he was doing when he first started.

“But he kept hammering away at it and he was improving all the time.”

McDonnell changed his life dramatically overnight, transforming himself from joker to dedicated boxer, even before he had been granted a license to compete.

SM: “If he hadn’t gone to the gym and got focused on something, we wouldn’t have been together.

“On a weekend he was more bothered about going out with his mates.

“He needed something to focus on rather than going out with friends.

“It turned his life upside down.”

It quickly became clear McDonnell was nothing but serious about following his brother into the sport.

SB: “After about six months I sat him down and asked how serious he was about fighting and he said very.

“So we applied for a license. With him having no amateur experience, they put him through tests, watching him spar and doing fitness tests.

“Eventually they agreed for him to fight.”

A few fights brought signs of progression and plenty of comparisons with his brother but expectations remained low.

Surely he had too much catching up to do to make anything significant of himself in the sport.

JM: “I never really thought about it too much, how far he’d go.

“You take everything a step at a time and don’t really look too far in front.

“All I was seeing from him was improvement and the fact he was working his socks off in the gym.

“He’d got a lot of determination about him so when you think back, it’s not that much of a surprise that he started picking up titles.”

SB: “Looking at it, a Central Area title or an English title looked as though it would be the pinnacle for him.

“And I really do think, at one point, Gav would have been happy with that.

“But in his seventh fight, he was Central Area champion.

“And that’s just how the story goes from there.”

Alongside his management duties, Bull was also promoting his own shows at Doncaster Dome with McDonnell as one of his key players.

But, for any small hall promoting, running profitable shows is not easy.

SB: “It quickly got to a stage where I was having to bring opponents in who were ticket sellers, which generally means the fights are tougher.

“It always seemed to fall that Jamie was fighting a few weeks before or after, usually on big Sky shows for international titles.

“So fans of them both would obviously be choosing Jamie’s show to go to.

“You go back then to the Scott Gladwin fight where Gav won the Central Area title.

“Gladwin was unbeaten and fancied. Gav was up against it but he breezed through.

“And he breezed through plenty. Paul Economides, Ross Burkinshaw.

“Then I manage to get him in against Josh Wale in a British title eliminator. That was massive, and really tough.

“But he came through it so well and he’d got a British title fight in his 12th fight.”

That British title fight was against Leigh Wood, a tricky Ingle-trained fighter who was unbeaten and tipped to win comfortably.

As was typical however, McDonnell eased through, recovering from a slow start to stop Wood within six rounds.

On his first Sky outing, it announced him to the wider boxing public as one to watch. But it also did closer to home.

SM: “That night in Hull when he won the British title was when I knew he could do big things.

“It was him moving from the Dome to a Sky show, that’s when you realise it was serious.

“Everything after that got more serious. The dieting, training, press conferences. Everything gets more serious and more focused.”

SB: “From there, there was no stopping him.

“He ended up in some massive tests. We opted to defend against Josh Wale. Who would do that? And it ended up being massively tough.

“Since his sixth fight, every opponent has had a winning record.

“Vusi Malinga was a massive test.

SM: “When he fought Malinga, I didn’t want to go. It was supposed to be tough and I was scared.”

SB: “Malinga had been the distance with Leo Santa Cruz. And his fight before facing Gav was for the IBF title when he lost to Stuey Hall.

“But it was a chance for a world ranking and a WBO intercontinental title. He was never going to turn it down.

“And then he wins, and he wins fairly comfortably.

“At that point, it’s when you start thinking there could be no stopping this kid.”

In his next fight, in March 2015, McDonnell won the vacant European super bantamweight title, dominating Oleksandr Yegorov.

In the months which followed, he switched trainers, leaving Hulley to join up with Rotherham-based Dave Coldwell.

Coldwell manages brother Jamie and was called on at late notice to work his corner for his world title defence against Tomoki Kameda in Texas after Hulley’s crippling fear of flying preventing him from travelling.

Gavin was impressed by what he saw from Coldwell in America and made a decision on his return to England.

Dave Coldwell: “When he came home he came into the gym, asked if he could do a couple of sessions and he’s never left.”

Coldwell immediately felt like he had plenty of work on his hands.

DC: “When I took him on the pads in Texas, I couldn’t believe he’d got beyond domestic level to be blunt. He just didn’t have it for me.

“But that’s where he gets a tremendous amount of respect from me.

“He’s very much like Curtis Woodhouse in that he’s not got a massive amount of natural talent but he’s got an incredible work ethic.

“He’ll work his socks off to improve constantly. Just like Curtis did, he wants to be successful and he’ll do everything he can to achieve.

“I’ve seen plenty of fighters with a lot more natural talent than Gavin never achieve half of what he’s achieved. Pure hard work can take you a long way and it has for him.”

That hard work has certainly taken him a long way and has put him on the verge of world title glory this weekend.

His task is a tough one. Opponent Vargas is highly fancied and is a knockout specialist.

But there is no surprise that those closest to him are backing him to claim the WBC title on Saturday night.

DC: “He is improving constantly. You saw a big jump in him in the Jeremy Parodi fight because that was a test. And he’s just improved on that.

“In his last five or six spars for this fight he’s been on the money. His concentration in fights has been something that’s let him down but I’ve not seen much in these spars to worry me about that.

“It’s been an incredible story for him so far and I really think it’ll carry on on Saturday.”

JM: “I wouldn’t say he could do it if I didn’t think he could. We’re honest with each other.

“But I definitely think he can do it.”

SB: “We know he’s got it tough. There’s no doubt about it.

“But how can you count him out with what he’s managed to come through so far?

“He’s got so much determination and so much drive.

“No one would deserve it more. Even if he doesn’t do it on Saturday, if I never achieve anything more in boxing, I can be happy. What he’s done already is incredible.

“He’s a down to earth kid, with a nice normal family, a wife who backs him all the way.

“He deserves everything he’s achieved.”

SM: “I’m so proud of him. I’ve been proud of him from the start of it and I’ll be proud of him whatever happens.